1ntp_misc(5) File Formats Manual ntp_misc(5)
2
6 ntp_misc - Miscellaneous Options
7 broadcastdelay seconds
10 The broadcast and multicast modes require a special calibration
11 to determine the network delay between the local and remote
12 servers. Ordinarily, this is done automatically by the initial
13 protocol exchanges between the client and server. In some
14 cases, the calibration procedure may fail due to network or
15 server access controls, for example. This command specifies the
16 default delay to be used under these circumstances. Typically
17 (for Ethernet), a number between 0.003 and 0.007 seconds is
18 appropriate. The default when this command is not used is 0.004
19 seconds.
20 calldelay delay
22 This option controls the delay in seconds between the first and
23 second packets sent in burst or iburst mode to allow additional
24 time for a modem or ISDN call to complete.
25 driftfile driftfile [ minutes [ tolerance ] ]
27 This command specifies the complete path and name of the file
28 used to record the frequency of the local clock oscillator.
29 This is the same operation as the -f command linke option. If
30 the file exists, it is read at startup in order to set the ini‐
31 tial frequency and then updated once per hour with the current
32 frequency computed by the daemon. If the file name is speci‐
33 fied, but the file itself does not exist, the starts with an
34 initial frequency of zero and creates the file when writing it
35 for the first time. If this command is not given, the daemon
36 will always start with an initial frequency of zero. The file
37 format consists of a single line containing a single floating
38 point number, which records the frequency offset measured in
39 parts-per-million (PPM). The file is updated by first writing
40 the current drift value into a temporary file and then renaming
41 this file to replace the old version. This implies that ntpd
42 must have write permission for the directory the drift file is
43 located in, and that file system links, symbolic or otherwise,
44 should be avoided.
45 The two optional values determine how often the file is writ‐
47 ten, and are particuarly useful when is it desirable to avoid
48 spinning up the disk unnecessarily. The parameter minutes is
49 how often the file will be written. If omitted or less than 1,
50 the interval will be 60 minutes (one hour). The parameter tol‐
51 erance is the threshold to skip writing the new value. If the
52 new value is within tolerance percent of the last value written
53 (compared out to 3 decimal places), the write will be skipped.
54 The default is 0.0, which means that the write will occur
55 unless the current and previous values are the same. A toler‐
56 ance of .1 equates roughly to a difference in the 2nd decimal
57 place.
58 enable [ auth | bclient | calibrate | kernel | monitor | ntp | pps |
61 stats]
62 disable [ auth | bclient | calibrate | kernel | monitor | ntp | pps |
64 stats ]
65 Provides a way to enable or disable various system options.
66 Flags not mentioned are unaffected. Note that all of these
67 flags can be controlled remotely using the ntpdc utility pro‐
68 gram.
69 auth Enables the server to synchronize with unconfigured
71 peers only if the peer has been correctly authenticated
72 using either public key or private key cryptography.
73 The default for this flag is enable.
74 bclient Enables the server to listen for a message from a
76 broadcast or multicast server, as in the multicast‐
77 client command with default address. The default for
78 this flag is disable.
79 calibrate
81 Enables the calibrate feature for reference clocks. The
82 default for this flag is disable.
83 kernel Enables the kernel time discipline, if available. The
85 default for this flag is enable if support is avail‐
86 able, otherwise disable.
87 monitor Enables the monitoring facility. See the ntpdc program
89 and the monlist command or further information. The
90 default for this flag is enable.
91 ntp Enables time and frequency discipline. In effect, this
93 switch opens and closes the feedback loop, which is
94 useful for testing. The default for this flag is
95 enable.
96 pps Enables the pulse-per-second (PPS) signal when fre‐
98 quency and time is disciplined by the precision time
99 kernel modifications. See the A Kernel Model for Preci‐
100 sion Timekeeping page for further information. The
101 default for this flag is disable.
102 stats Enables the statistics facility. See the Monitoring
104 Options page for further information. The default for
105 this flag is disable
106 includefile includefile
109 This command allows additional configuration commands to be
110 included from a separate file. Include files may be nested to a
111 depth of five; upon reaching the end of any include file, com‐
112 mand processing resumes in the previous configuration file.
113 This option is useful for sites that run ntpd on multiple
114 hosts, with (mostly) common options (e.g., a restriction list).
115 logconfig configkeyword
117 This command controls the amount and type of output written to
118 the system syslog facility or the alternate logfile log file.
119 All configkeyword keywords can be prefixed with =, + and -,
120 where = sets the syslogmask, + adds and - removes messages.
121 syslog messages can be controlled in four classes (clock, peer,
122 sys and sync). Within these classes four types of messages can
123 be controlled: informational messages (info), event messages
124 (events), statistics messages (statistics) and status messages
125 (status). Configuration keywords are formed by concatenating
126 the message class with the event class. The all prefix can be
127 used instead of a message class. A message class may also be
128 followed by the all keyword to enable/disable all messages of
129 the respective message class. By default, logconfig output is
130 set to allsync. Thus, a minimal log configuration could look
131 like this:
132 logconfig=syncstatus +sysevents
134 This would just list the synchronizations state of ntpd and the
137 major system events. For a simple reference server, the follow‐
138 ing minimum message configuration could be useful:
139 logconfig=allsync +allclock
142 This configuration will list all clock information and synchro‐
145 nization information. All other events and messages about
146 peers, system events and so on is suppressed.
147 logfile logfile
151 This command specifies the location of an alternate log file to
153 be used instead of the default system syslog facility. This is
154 the same operation as the -l command line option.
155 phone dial1 dial2 ...
159 This command is used in conjunction with the ACTS modem driver
160 (type 18). The arguments consist of a maximum of 10 telephone
161 numbers used to dial USNO, NIST or European time services. The
162 Hayes command ATDT is normally prepended to the number, which
163 can contain other modem control codes as well.
164 setvar variable [default]
167 This command adds an additional system variable. These vari‐
168 ables can be used to distribute additional information such as
169 the access policy. If the variable of the form name = value is
170 followed by the default keyword, the variable will be listed as
171 part of the default system variables (ntpq rv command). These
172 additional variables serve informational purposes only. They
173 are not related to the protocol other that they can be listed.
174 The known protocol variables will always override any variables
175 defined via the setvar mechanism. There are three special vari‐
176 ables that contain the names of all variable of the same group.
177 The sys_var_list holds the names of all system variables. The
178 peer_var_list holds the names of all peer variables and the
179 clock_var_list holds the names of the reference clock vari‐
180 ables.
181 tinker [ allan allan | dispersion dispersion | freq freq | huffpuff
183 huffpuff | panic panic | step step | stepout stepout ]
184 This command can be used to alter several system variables in
185 very exceptional circumstances. It should occur in the configu‐
186 ration file before any other configuration options. The default
187 values of these variables have been carefully optimized for a
188 wide range of network speeds and reliability expectations. In
189 general, they interact in intricate ways that are hard to pre‐
190 dict and some combinations can result in some very nasty behav‐
191 ior. Very rarely is it necessary to change the default values;
192 but, some folks can't resist twisting the knobs anyway and this
193 command is for them. Emphasis added: twisters are on their own
194 and can expect no help from the support group. The variables
195 operate as follows:
196 allan allan
199 The argument becomes the new value for the Allan inter‐
200 cept, which is a parameter of the PLL/FLL clock disci‐
201 pline algorithm. The value is in seconds with default
202 1500 s, which is appropriate for most computer clocks.
203 dispersion dispersion
205 The argument becomes the new value for the dispersion
206 increase rate, normally .000015 s/s.
207 freq freq
209 The argument becomes the initial value of the frequency
210 offset in parts-per-million. This overrides the value
211 in the frequency file, if present, and avoids the ini‐
212 tial training state if it is not.
213 huffpuff huffpuff
215 The argument becomes the new value for the experimental
216 huff-n'-puff filter span, which determines the most
217 recent interval the algorithm will search for a minimum
218 delay. The lower limit is 900 s (15 m), but a more rea‐
219 sonable value is 7200 (2 hours). There is no default,
220 since the filter is not enabled unless this command is
221 given.
222 panic panic
224 The argument is the panic threshold, by default 1000 s.
225 If set to zero, the panic sanity check is disabled and
226 a clock offset of any value will be accepted.
227 step step
229 The argument is the step threshold, by default 0.128 s.
230 It can be set to any positive number in seconds. If set
231 to zero, step adjustments will never occur. Note: The
232 kernel time discipline is disabled if the step thresh‐
233 old is set to zero or greater than the default.
234 stepout stepout
236 The argument is the stepout timeout, by default 900 s.
237 It can be set to any positive number in seconds. If set
238 to zero, the stepout pulses will not be suppressed.
239 trap host_address [port port_number] [interface interface_address]
242 This command configures a trap receiver at the given host
243 address and port number for sending messages with the specified
244 local interface address. If the port number is unspecified, a
245 value of 18447 is used. If the interface address is not speci‐
246 fied, the message is sent with a source address of the local
247 interface the message is sent through. Note that on a multi‐
248 homed host the interface used may vary from time to time with
249 routing changes. The trap receiver will generally log event
250 messages and other information from the server in a log file.
251 While such monitor programs may also request their own trap
252 dynamically, configuring a trap receiver will ensure that no
253 messages are lost when the server is started.
254 ttl hop ...
257 This command specifies a list of TTL values in increasing
258 order. up to 8 values can be specified. In manycast mode these
259 values are used in turn in an expanding-ring search. The
260 default is eight multiples of 32 starting at 31.
261
264 ntp.drift frequency compensation (PPM)
265
267 ntp.conf(5)
268 Primary source of documentation: /usr/share/doc/ntp-*
270 This file was automatically generated from HTML source.
272 ntp_misc(5)